Retractable blade knife



FIG. 1 is a perspective view of a retractable blade knife showing my new design with the blade in a retracted position;

FIG. 2 is a top plan view thereof with the blade in an extended position;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a front elevational view thereof with the blade in an extended position; and,

FIG. 7 is a rear elevational view thereof with the blade in an extended position. 

The ornamental design for a retractable blade knife, as shown and described. 